Ok, I can access my home PC from almost everywhere: friends, WLAN cafes, internet shop.
But I cannot access it from my banks office.
After some investigations I found the reason: The bank has an inhouse
proxy. All internet web page traffic is passed through proxies. When I call
e.g. www.google.com from my work PC then this page request is at first
sent to the proxy. This proxy fetches in turn the web page, put the
returned HTML code into its proxy buffer and send a copy to my PC.
Obviously this architecture does NOT work with VNC requests.
Yes, I set the HTTP port of my UltraVNC server to 80.
Hence port filtering (e.g. by firewalls) should not be the issue because the
software could not distinguish between a "normal" browser web page request and a VNC request on port 80.
NAT2NAT does not help because it is not a NAT forwarding problem.
It must be the proxy. The proxy gets some undefinable VNC data stuff
from my VNC server. Intelligent analysis by the proxy software shows that there is no HTML code. Hence the proxy denied the transfer to my computer inside the LAN.
Is my point of view correct?
Did anyone else experienced the same situation?
Are there any work arounds ?
Update: UltraVNC 1.4.3.6 and UltraVNC SC 1.4.3.6: https://forum.uvnc.com/viewtopic.php?t=37885
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Most evil enemies of (Ultra)VNC: proxies !!
Yep. Ther's a workaround that could trick the proxy smart analysis of the packets.
I remember a java proxy that had been developped about 2 years ago that was able to embed the VNC binary packets into dummy HTML tags to fool the smart firewalls.
I have to retrieve the url...
This combined with Nat2Nat could do the trick.
But I'm also glad to hear that a bank site is correctly secured
I remember a java proxy that had been developped about 2 years ago that was able to embed the VNC binary packets into dummy HTML tags to fool the smart firewalls.
I have to retrieve the url...
This combined with Nat2Nat could do the trick.
But I'm also glad to hear that a bank site is correctly secured
UltraSam
